Editor’s note: The following was adapted from an article in Choices, a publication of the Agricultural & Applied Economics Association, written by Diane Charlton, J. Edward Taylor, Stavros Vougioukas, and Zachariah Rutledge.
MILWAUKEE, Wis. — A diminishing farm labor supply puts pressure on the agricultural sector to adopt new technologies for difficult-to-mechanize tasks.
The competitiveness of U.S. agriculture, as well as the welfare of farm workers and the communities in which they live, depends on how we as a society adapt to a new era of farm labor scarcity.
Technologies that were relatively inexpensive to develop and adopt have been in commercial use for many years.
The tightening of the farm labor supply today creates incentives to develop and adopt more challenging — and more expensive — labor-saving solutions.
Technology in orchard
Tree fruits are some of the most labor-intensive crops grown in the United States today, and viable technologies to reduce labor requirements are on the horizon for only a few varieties.
Nearly all fresh-market fruits and vegetables are hand harvested, creating high demand for seasonal labor.
Existing mass-harvesting methods such as trunk or canopy shaking result in unacceptable fruit damage and cannot be used selectively to harvest fruits that do not ripen uniformly.
Canopy and crop load-management operations, like pruning and flower and fruit thinning, are also manual and labor intensive.
These activities require advanced perception and dexterous manipulation capabilities, and they have to be performed reliably in a fast, cost-effective manner.
To address these challenges, engineers from academia and industry are developing “intelligent” robotic solutions for some of the most labor-intensive tasks.
Commonly, such solutions need to be combined with changes in cultivars and/or horticultural practices.
The up-front costs of adopting robotics in the field will likely be high, and if the robots damage the fruits, the value of the end-product will decline.
These barriers would prevent adoption in markets with low wages and an elastic labor supply, but if the farm labor supply continues to tighten and wages continue to rise, robotics will be a critical step forward in keeping U.S. farms competitive in a global market.
What’s out there
Some examples of intelligent automated systems that have recently become commercially available or are on the horizon include automated lettuce thinners, integrated weed management systems and robotic apple harvesters (not yet commercially available).
Thinning lettuce is very labor intensive, and most lettuce fields in California used to be hand-thinned, typically using a hoe.
Several companies have introduced automated lettuce thinners that use machine vision and a spray system to remove unwanted plants.
Mosqueda et al. (2017) tested four automated thinners and reported that, on average, 2.03 person-hours and 7.31 person-hours per acre were needed to thin the lettuce plots with and without the machine, respectively.
The respective labor costs were estimated at $43.40 and $112.70 per acre, accounting for higher wage rates of equipment operators.
Integrated weed management (IWM) systems are essential for broccoli and lettuce.
A central part of IWM is physical weed removal. Currently, this removal is performed using standard cultivators that remove weeds between rows, followed by labor-intensive manual weeding inside the rows.
The cost of hand weeding ranges from $250 to $450 per hectare.
Recently, robotic cultivators have been commercialized to mechanize intra-row weeding.
These use computer vision to distinguish crop plants from weeds and activate high-speed blades to selectively destroy weeds.
Lati et al. (2016) evaluated a robotic cultivator and reported that it removed 18%-41% more weeds at moderate to high weed densities and reduced hand-weeding times by 20%-45% compared with the standard cultivator.
Other innovative robotic systems being developed by startup companies are at a precommercial stage.
For example, an apple-harvesting robot is being developed that uses computer vision to locate the fruits and a vacuum gripper on a robot arm to pick them.
Its developers have tested the robot on V-trellised trees thinned to single fruits inside the robot workspace and pruned to approximately 25 cm wide.
They report picking one apple per second with one robot arm. Given that one typical worker on an orchard platform picks approximately 1 apple per 1.5 seconds, the robotic arm could replace 1.5 pickers, and multifarm harvesters could replace small teams of pickers.
New innovations, new skills. Not only will labor demands decrease in response to technological improvements, but the skills required on-farm also will change.
Farm workers will increasingly include mechanics and engineers. Our educational system — including high schools, community colleges and universities — will have to prepare a generation of workers with the skills to manage new crop technologies.
Informational resources, including high-speed internet, will have to reach into the fields.
Rather than importing low-skilled farm workers, the United States might import agricultural engineers from Mexico, where universities currently produce twice as many engineers per capita as U.S. universities do.
New technologies make farm workers more productive, making it possible for farmers to pay higher wages to a smaller workforce.
Rising wages can benefit farm workers and the communities where they live, but only if workers have the skills that new technologies demand, and if lower-skilled workers can shift their labor from newly mechanized crops and tasks to others that are more difficult to mechanize.
About the authors
Diane Charlton (firstname.lastname@example.org) is assistant professor, Department of Agricultural Economics and Economics, Montana State University, Bozeman, Mont. J. Edward Taylor (email@example.com) is professor, Department of Agricultural and Resource Economics, University of California, Davis, Calif. Stavros Vougioukas (firstname.lastname@example.org) is associate professor, Department of Biological and Agricultural Engineering, University of California, Davis, Calif. Zachariah Rutledge (email@example.com) is Ph.D candidate, Department of Agricultural and Resource Economics, University of California, Davis, Calif.
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